Boiler construction



April 4, 1939.. c.. s. TURNER BOILER CONSTRUCTION i Filed June 25, 1936 lNvENToR CHARLES S.TURNER HON AT ORNEYS Patented Apr. 4, 1939 UNITED STATES PATENT GFFHCE 2 Claims.

'Ihis invention relates to the construction of boiler apparatus, and constitutes a continuation in part of my copending application Serial No. 743,069, filed September 7, 1934.

Not only in the installation of superheaters of the type described in said copending application, but in the construction of all boiler apparatus in which tubes or tube assemblies must be projected into or through boiler drums, the securance of the tubular elements with respect to the drums present problems of no little diculty and of extreme importance. Expanded joints are usually provided for ordinary boiler tubes, but these cannot always be kept tight, and if, as frequently occurs, water seeps into the space between the tube and-drum, the wetted joint soon gives trouble if alkalis or other harmful ingredients from water softeners, or due to other conditions, are present in the water. Since such boilers are assembled in the eld, however, and it is not feasible, and under most safety engineering codes it is not lawful, to weld in the field directly to a boiler drum,

for the reason that the strains so caused might result in failure of the drum, the expanded joint has been generally used as the best known expedient. Where also, as in the superheater construction disclosed in the aforementioned copending application, the tube assemblies are of irregular external conguration, it becomes literally impossible to expand them into the drum.

Contemplating the aforementioned considerations, the invention aims to provide improved means whereby boiler tubes or tubular elements, even though of irregular contour or complex cross section, may be projected through and sealed with relation to the wall of a boiler drum or the like, by means of a welded joint made in the eld, without danger of injury to the drum.

It is a further aim to provide such securance by means of a welded seal located at a distance from the drum in such fashion that the latter cannot be harmiully affected by the making of the weld, yet which does not interfere with or reduce the active surface of the tubular elements or incorporate parts which can be injured by the heat of the boiler or complicate its construction.

Another important object is the provision of improved securing means rendering i-t a simple matter to remove and reinstall such tubular elements, repeatedly if desired or necessary, without danger of injury to the drum, and'which insure constant maintenance of dry joints.

Other objects and advantages will be apparent from the following description, wherein reference is made to the accompanying drawing illustrating preferred embodiments of my invention and wherein similar reference numerals designate similar parts throughout the several views.

In the drawing:

Figure 1 is a diagrammatic and fragmentary vertical section of a marine boiler provided with a superheater incorporating tubular elements installed in accordance with the principles of this invention;

Figure 2 is an enlarged section of the upper drum, partly broken away, better illustrating the preferred manner of installing the superheater elements, which are projected through the drum wall;

Figure 3 is a cross section of one of the tube assemblies, taken on the line 3-3 of Figure 2, and

Figure 4 is a fragmentary view similar to Figure 2 of another embodiment.

Referring now to the drawing; reference character I designates the upper drum of a boiler, diagrammatically and only fragmentarily illustrated as of a type common in marine service, although the invention will be seen to be independent of the particular boiler apparatus. Between the drum l0 and the lower mud drum l2 water tubes I4 extend in the usual or any suitable fashion, and a radiant superheater assembly is shown arranged in front of the first row of water tubes. The shown superheater is of the Turner water-regulated type, the heat-absorbing elements comprising multi-passage assemblies of integrated water and steam tubes, secured together by longitudinal seam welding. Any of various cross sectional arrangements might be used; that best shown in Figure 3, and constituting the illustrative embodiment for present purposes, comprises a central water tube l5 having a fiuted exterior, in the utes of which are welded the encircling steam tubes Il. The water tubes may be fed at their lower extremities from the mud drum l2 through suitable valvular controlling means 20 and header means 2 I. At their upper ends the superheater elements extend through and into the upper drum Ill and are carried above the water level Il therein, where the water tubes discharge and the superheater tubes Il have their inlets, into which saturated steam flows, traveling downwardly through the units and discharging at their lower ends into steam pipe 22. This superheater installation, as stated, merely serves as an illustration of a situation calling for the attachment of tubes to a drum in the field under diicult conditions, for it will be seen that their configuration precludes their direct expansion in place in the drum.

Tightly secured in apertures suitably located in the drum are sleeves 25. These may of course be installed in the fabrication of the drum, and are in Figures 1 and 2 indicated as expanded in place. The sleeves are of such size that the tubular superheater assemblies may be slipped therethrough from beneath before the hats 26-21 and other accessory apparatus are secured to the tubes inside the drum. The sleeves may be of substantial length, several inches if desired, to allow for shortening thereof in event of repeated removal and reinstallation of units, as will presently appear. When the tube assemblies have been properly positioned, it is only necessary to weld them to the upper or inner ends f the sleeves, as indicated at 30, to effectively seal the drum and the units. Due. to the heat loss the drum is thus subjected to as great or as rapid temperature changes by the Welding, and embrittlement thereof is avoided.

In event it is later necessary to remove one of the units, it is merely necessary to cut off the sleeve and tube assembly at or directly below the Weld 30, after which the tube may be re- J moved from beneath, while of course the severed extremity Within the drum may be removed through the manhole of the drum, designated I3.

The modified construction shown in Figure 4 indicates sleeves 25St to be Welded, as at 24a, to the boiler drum Illa, While the boiler tubes llla are extended through the sleeves and Welded to the tops thereof, as at 30a. Inasmuch as sleeves 25a may be Welded to the drum in this manner during its fabrication, and the assembly thereafter annealed in the Shop to prevent any embrittlement which Would otherwise be apt to result from direct Welding to the drum and unrestricted cooling thereafter, it will be seen that a feasible method of completing the Welded attachment in the field may be provided in this fashion, as during assembly of the boiler the tubes lia need only be slipped into the sleeves and Welded to their ends, which Work may be done in the eld Without danger of injury to the drum. This construction is, as indicated, readily adaptable to such securance of either plain Water tubes vor more complicated assemblies, providing in either event a permanently tight and dry joint,

which nevertheless admits of ready detachment and re-insertion of the tubes in the eld.

While it will be apparent that the illustrated embodiments of my invention herein disclosed are Well calculated to adequately fulll the objects and advantages primarily stated, it is to be understood that the invention is susceptible to variation, modication and change Within the spirit and scope of the subjoined claims.

What I claim is: v

1. Boiler apparatus comprising in` combination with a metallic drum adapted to contain iiuid, a plurality of tubes grouped to form a unitary assembly and projecting into an opening in the drum, and means for securing and sealing such tube assembly with respect to the drum, comprising a sleeve element expanded and tightly fitted into the drum and projecting from the surface thereof, said tube assembly being extended into the sleeve element and Welded thereto at a point spaced from the drum.

2. Boiler apparatus comprising in combination with a metallic drum adapted to contain fluid, a. plurality of tubes grouped to form a unitary assembly and projecting into an opening in the drum, and means for securing and sealing such tube assembly with respect to the drum, comprising a sleeve elementexpanded and tightly fitted into the opening in the drum and extending through and into the space within the same, said tube assembly being extended through the sleeve element and into the drum, and being Welded to the end of the sleeve element Within the drum.

CHARLES S. TURNER. 

